The present invention relates generally to fluid dispensing apparatus and more particularly, to an apparatus for dispensing high viscosity paints and pigments therefor.
Dispensing machines are commonly used in the art of paint mixing to dispense desired amounts of colorants into a base medium to make a certain color. Typically, known dispensing machines have utilized a plurality of dispensing reservoirs in the form of hollow cylinders with each reservoir having its own dispensing valve. The large number of reservoirs required a large amount of space. Some of these machines are used to perform volumetric mixing, that is, certain amounts of colorants are individually dispensed by volume from their respective supply reservoirs. Furthermore, such dispensing is done by relying on the force of gravity, and therefore such types of dispensing machines are only feasible with low viscosity colorants that are conducive to gravity flow.
In instances when paints or inks are mixed using high viscosity inks or paints, such as in the silk-screening arts, it is impractical to use the machines described above, primarily because of the high viscosity of the fluid medium being dispensed which can range from about 15,000 to about 175,000 Centipoise. In order to overcome this disadvantage, some dispensing apparatus have been developed in the form of complex dispensers that utilize a plurality of high pressure pumps, with one pump being associated with each supply reservoir. The large number of pumps not only significantly increases the cost of such a machine and the large number of pigment or colorant reservoirs, but also increases the floor space required for the machine.
The present invention is directed to a dispensing apparatus for dispensing high-viscosity colorants, such as in the form of pigment concentrates, that overcomes the disadvantages of the prior art as described above.